Mine worsens in loud environments and it seems it is more prevalent choice among us, I wonder why is that. It may have to do something with the fact that we don't hear our voice clearly, but IDK. Note that I still can talk completely fluently when talking to myself in loud environment. Recently we had a poster session in our university PhD conference and all posters were packed next to each other so a lot of people were talking simultaneously . And of course I really struggled to present my work xD. The funny part is that most people know me to be more or less fluent but here I stuttered almost on each word... I wish this disorder would be more consistent, but it is extremely variable for me, I can talk perfectly in some situations and barely able to say a word in others...